package day0722;

public class test1 {
    public static void main(String[] args) {
        Object a=new Child();
        if (a instanceof Person){
            Person a1=(Child)a;
            a1.grow();
        }
    }
}
interface Person{
    void grow();
}
class Child implements Person{
    public void grow(){
        System.out.println("Adult");
    }
}